STATEMENT OF PROBLEM: Zirconia-based restorations have the common technical complication of delamination, or porcelain chipping, from the zirconia core. Thus the shear bond strength between the zirconia core and the veneering porcelain requires investigation in order to facilitate the material's clinical use. PURPOSE: The purpose of this study was to evaluate the bonding strength of the porcelain veneer to the zirconia core and to other various metal alloys (high noble metal alloy and base metal alloy). MATERIAL AND METHODS: 15 rectangular (4x4x9mm) specimens each of zirconia (Cercon), base metal alloy (Tillite), high noble metal alloy (Degudent H) were fabricated for the shear bond strength test. The veneering porcelain recommended by the manufacturer for each type of material was fired to the core in thickness of 3mm. After firing, the specimens were embedded in the PTFE mold, placed on a mounting jig, and subjected to shear force in a universal testing machine. Load was applied at a crosshead speed of 0.5mm/min until fracture. The average shear strength (MPa) was analyzed with the one-way ANOVA and the Tukey's test (alpha= .05). The fractured specimens were examined using SEM and EDX to determine the failure pattern. RESULTS: The mean shear strength (+/- SD) in MPa was 25.43 (+/- 3.12) in the zirconia group, 35.87 (+/- 4.23) in the base metal group, 38.00 (+/- 5.23) in the high noble metal group. The ANOVA showed a significant difference among groups, and the Tukey's test presented a significant difference between the zirconia group and the metal group. Microscopic examination showed that the failure primarily occurred near the interface with the residual veneering porcelain remaining on the core. CONCLUSION: There was a significant difference between the metal ceramic and zirconia ceramic group in shear bond strength. There was no significant difference between the base metal alloy and the high noble metal alloy.
Ceramics ; Collodion ; Dental Porcelain ; Fires ; Fungi ; Polytetrafluoroethylene ; Shear Strength ; Zirconium

No abstract available.
Cerebral Hemorrhage* ; Mucormycosis*

Otologic complaints, including otalgia, tinnitus, vertigo, and hearing loss, are known to be related to temporomandibular disorders (TMDs). There have been several hypotheses regarding the clinical correlation between otologic complaints and TMDs, based on clinical phenomena with corresponding symptoms, the close neurological relationship between otic and masticatory structures, and anatomical features of the tympanic cavity and jaw joint. Function of the tensor tympani muscle seems to be crucial to understanding TMD-related otologic symptoms. The tensor tympani inserts into the handle of the malleus and it modulates sound transduction in situations of excessive noise. This muscle is innervated by the trigeminal nerve, like the masticatory muscles. Voluntary eardrum movement by pathological tensor tympani contraction results in various otologic symptoms. Thus, co-contraction of the tensor tympani with the masticatory muscle could be a possible cause of TMD-related otologic symptoms. The tensor tympani is rather unrelated to the acoustic reflex, in which the stapedius is strongly involved. The tensor tympani seem to be controlled by proprioceptive information from the trigeminal sensory nucleus. The peripheral innervation pattern of the tensor tympani and masticatory muscles is also supposed to be interconnected. The middle ear structure, including the malleus, incus, and tensor tympani, of mammals had been adapted for acoustic function and lacks the masticatory role seen in non-mammalian jawed vertebrates. The tensor tympani in non-mammals is one of the masticatory muscles and plays a role in the modulation of sound transduction and mastication. After the functional differentiation of the mammalian middle ear, the nervous connection of the tensor tympani with other masticatory apparatus still remains. Through this oto-stomatognathic vestige, the tensor tympani seems to contract unnecessarily in some pathological conditions of the TMD in which the masticatory muscles contract excessively. We hypothesized that the phylogenic relationship between the tensor tympani and masticatory apparatus is a significant and logical reason for TMD-related otologic complaints.
Acoustics ; Ear, Middle ; Earache ; Hearing Loss ; Incus ; Jaw* ; Joints ; Logic ; Malleus ; Mammals ; Mastication ; Masticatory Muscles ; Noise ; Reflex, Acoustic ; Stapedius ; Temporomandibular Joint Disorders ; Tensor Tympani* ; Tinnitus ; Trigeminal Nerve ; Tympanic Membrane ; Vertebrates ; Vertigo

The success of porcelain laminate veneer depends on the bond strength between tooth structure and ceramic restoration and the design of tooth preparation. In particular, incisal coverage and incisal finish line are the two most important factors in long-term fracture resistance. Although the majority of clinicians are practicing incisal coverage and there are various opinions on the geometrical ratio between the clinical crown length of the remaining tooth structure and the length of incisal extension in porcelain laminate veneer and the optimal incisal finish lines, scientific evidence still leaves much to be desired. The purpose of this study was to determine the effects of the amounts of incisal coverage and the types of incisal finish line on th stress distribution in maxillary anterior porcelain laminate veneers under two different loading conditions. Three-dimensional finite element models of a maxillary anterior porcelain veneer with different amounts of incisal coverage ; 0, 1, 2, and 3mm and different incisal finish lines ; feathered edge, incisal bevel, reverse bevel and lingual chamfer with various amounts of lingual extension were developed. 300N force was applied at the point 0.5mm cervical of the linguoincisal edge in two loading conditions ; A) 125 degrees, B) 132 degrees. tensile and compressive stress in ceramic and shear stress in the resin cement layer wee analyzed using three-dimensional finite element method. The results were as follows : 1. The types of incisal finish line had more influence on the stress distribution in porcelain laminate veneer than the amounts of incisal coverage. 2. In case of no incisal coverage, incisal beveled laminate exhibited more evenly distributed tensile stress than feathered edged laminate. And in case of incisal coverage, reverse beveled laminate and lingual chamfered laminate with 1mm lingual extension exhibited more evenly distributed tensile stress than lingual chamfered laminates with 2 mm and 3mm lingual extension. 3. As long as the lingual chamfer goes, less tensile stress was found at the incisal edge, while much more tensile stress was found at the lingual margin area in proportion to length of lingual extension. 4. Under 125 degree load, tensile stress in porcelain laminate veneer had increased compared with that under 132 degree load and the difference exhibited by the change of the amount of tooth support was larger. 5. The types of incisal finish line and the distance from the incisal finish line to the loading point had more influence on the shear stress distribution in the resin cement layer than the amount of incisal coverage. In contrast loading condition had little influence.
Animals ; Ceramics ; Crowns ; Dental Porcelain* ; Feathers ; Finite Element Analysis* ; Resin Cements ; Tooth ; Tooth Preparation

No abstract available.
Cartilage*

No abstract available.
Lupus Erythematosus, Systemic*

OBJECTIVES: We performed anterior spinal fusion and instrumentation in treatment of spinal tuberculosis. The clinical results of this operation and metal-related complications were evaluated to determine the rationale of anterior instrumentation in active tuberculous lesion. METHODS: From July 1989 to February 1993, we treated twenty-one patients with spinal tuberculosis by radical resection of the tuberculous lesion and bone grafting, followed by anterior instrumentation using Zielke rod system. The changes in spinal deformity were measured from lateral spinal radiographs obtained preoperatively and postoperatively at 3 months, 6 months, 1 year, 2 years and final follow-up. The recurrence of infection and possible complications were also observed clinically and radiologically. RESULTS: The mean kyphotic angle was decreased preoperatively from 21 degrees to 16 degrees at final follow-up in patients with thoracolumbar tuberculous lesions. The mean deformity angle was corrected 7 degrees in thoracolumbar tuberculosis and 12 degrees in lumbar tuberculosis compared with the preoperative deformity angle. There was not any persistence or recurrence of infection possibly related to the instrumentation. All patients were allowed early ambulation with the aid of a light brace. CONCLUSION: The clinical and radiological results suggested that the anterior instrumentation seemed to be one of the rational approaches for providing immediate stability in treating severe spinal tuberculosis without any significant risk of persistence or recurrence of infection.
Bone Transplantation ; Braces ; Congenital Abnormalities ; Early Ambulation ; Follow-Up Studies ; Humans ; Recurrence ; Spinal Fusion ; Tuberculosis ; Tuberculosis, Spinal*

The high variability of measured olfactory thresholds in humans reflects very broad range of sensitivity within and among individuals. This can be derived from the strongly compressive nature of olfaction, which makes it relatively hard to compare the size of two stimuli in odor sensation. However, we know that some portion of the variation is the result of extrinsic factors e.g. the method used to measure the olfactory threshold. For this reason, in order to address the bias and reliability of a psycophysical method, we combined the use of the CCCRC (Connecticut Chemosensory Clinical Research Center) test with the step method in 40 normal Korean adults twice a week for the evaluation of threshold. The measured thresholds showed high test-retest reliability and the threshold estimates remained consistent during the testing without trial-biases. Based on the results, we can conclude that a combined test using the CCCRC test and step method can be used in the measurement of olfactory threshold in a clinical context.
Adult* ; Bias (Epidemiology) ; Humans ; Odors ; Sensation ; Smell

STUDY DESIGN: This is a prospective study of 85 patients. OBJECTIVES: We wanted to identify the changes of ROM and sagittal alignment of the cervical spine after laminoplasty, and we wanted to determine the preoperative factors affecting the ROM and sagittal alignment of the cervical spine after laminoplasty. SUMMARY OF THE LITERATURE REVIEW: Cervical laminoplasty is an effective procedure for decompressing multilevel spinal cord compression. It has been reported that the ROM of the cervical spine was decreased after laminoplasty. It is well known that preoperative lordosis of the cervical spine is prerequisite for performing laminoplasty. Maintaining the postoperative lordosis of the cervical spine is also important for decompressing the spinal cord after laminoplasty. MATERIALS AND METHODS: Eighty-five patients who underwent open door laminoplasty from the C3 to C7 levels were prospectively studied. The minimum follow-up was two-years. The preoperative diagnosis was cervical spondylotic myelopathy (CSM) for 52 patients, ossification of the posterior longitudinal ligament (OPLL) for 29 patients and multilevel cervical disc herniation for 4 patients. Plain cervical spine lateral radiography in the neutral, flexion and extension positions was performed preoperatively and at the two-year follow-up. The cervical lordosis or kyphosis was measured by Cobb's method. The diagnosis, degree of preoperative lordosis in the neutral position, and the degree of preoperative sagittal alignment in flexion and extension were studied as the risk factors for postoperative kyphosis. RESULTS: The preoperative ROM of the cervical spine was 29.2 degrees and the postoperative ROM was 20.3 degrees. Therefore, 30.5% of the preoperative ROM was decreased after laminoplasty. A decreased ROM of more than 50% was found in 13 patients (15.3%). Their diagnosis was CSM in 11 patients (11/52, 21.1%) and OPLL in 2 patients (2/29, 6.9%). There were no significant differences in preoperative ROM between the two groups with decreased ROM being noted in more than 50% of the patients and decreased ROM being noted in less than 50% of the patients. The preoperative lordotic angle in the neutral position was 16.2 degrees and the postoperative lordotic angle was 11.4 degrees. Kyphosis (mean: 12.2 degrees) developed in 9 patients (9/85, 10.6%) after the surgery. Their preoperative diagnosis was CSM in all patients. The preoperative lordotic angle was significantly less in the kyphotic group than in the lordotic group. The preoperative flexion was 10.2 degrees greater and the preoperative extension was 10.3 degrees less in the kyphotic group than in lordotic group. The preoperative flexion angle was 19.3 degree kyphosis and the extension angle was 8.7 degree lordosis in the kyphotic group. CONCLUSIONS: The ROM of the cervical spine was decreased 30.5% after laminoplasty. Kyphosis developed in 10.6% of the patients. The preoperative factors affecting postoperative kyphosis were the diagnosis of CSM, a preoperative lordosis less than 10 degrees and a greater preoperative flexion angle than the extension angle. Therefore, kyphosis after laminoplasty was expected in a patient with the above three preoperative factors, so other treatment options such as instrumented fusion should be considered.
Animals ; Diagnosis ; Follow-Up Studies ; Humans ; Kyphosis ; Longitudinal Ligaments ; Lordosis ; Prospective Studies ; Radiography ; Range of Motion, Articular* ; Risk Factors ; Spinal Cord ; Spinal Cord Compression ; Spinal Cord Diseases ; Spine*

Placental site trophoblstic tumor(PSTT) is a rare variant of trophoblastic disease. This type of trophoblastic tumor apparently exhibits different biologic behaviors as compared with choriocarcinoma. Diagnosis is made by finding a predominance of intermediate trophoblasts and absence of fetal tissue in the dilatation and currettage specimens. The intermediate trophoblastic cells produce relatively little beta-hCG and hPL and unlike other trophoblastic tumors, they are frequently resistant to chemotherapy1. But patients with metastasis frequently exhibit a progression of disease and die despite of aggressive multiagent chemotherapy. We report a case of PSTT, in which a 36-year-old woman presented with vaginal bleeding after D&CB at 14 weeks of pregnancy. Despite of blood transfusion, the patient was under shock state, and hysterectomy was done. After hysterectomy, the pathological diagnosis was PSTT confirmed by immunohistochemical study, and the result was strong positive for hPL & cytokeratin but weak positve for beta-hCG2.
Adult ; Blood Transfusion ; Choriocarcinoma ; Diagnosis ; Dilatation ; Drug Therapy ; Female ; Fetus ; Humans ; Hysterectomy ; Keratins ; Neoplasm Metastasis ; Pregnancy ; Shock ; Trophoblastic Neoplasms ; Trophoblastic Tumor, Placental Site* ; Trophoblasts ; Uterine Hemorrhage